Use of DSC alerts?

The graphic WAS funny

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I'm not talking about speaking on the set, that has to be the same, whether DSC or not. The DSC messages though are digital, and are supposed to carry futher than voice

I'm not sure I believe it either, but it's commonly put about.

I'm agnostic on this one. Yes digital can have error handling safeguards built in, like computer networks, to ensure data is received and understood correctly, while voice can't, so dodgy connection will be better than voice over long distance.

Never looked into DSC protocols though. Maybe I should. Never interested me until now
 
No I'm not a "geek", just been around radio systems all my life, both for business and pleasure long long before I had a boat...which is why I dont go round teaching people sailing.
But, I firmly beleive that not only should the course teach operating procedures, but it should also teach correct installation techniques, a BASIC understanding of how the system works..ie the relationship between frequency and wavelength and antenna length, how to correctly solder a PL259 plug..the importance of using the correct impedance cable...the consequences of poor antenna matching, the importance of good grounding and all the other little things vital to having a useable workable emergency radio system, including connecting a GPS to the radio, and the different types of antenna available and the function of antenna "gain"
None of this extremely simple stuff is particularly "geeky", and I could teach all of that in under two hours to anybody with average intelligence.

You can teach someone all the procedures you like...but their procedures are not going to come in very handy when they are ten miles out and find that the dodgy installation which worked fine in the marina cant raise diddlysquat on the air.
You seem to think that procedures are enough and hide behind these, but in my view they are not, and the RYA's whole approach to radio, how and what they teach in it, and the level of tuition available needs a drastic overhaul.
Procedures and how to use the equipment are excellent for keeping discipline within the band, and I'm a great beleiver in that, but they are only part of the knowledge required to be conversant with the system.
It's a bit like me saying to you, yeah we'll do the day skipper course but I dont want you to teach me anything about buoys and lights.

Steve.
 
This is a DSC operation course. Most people have DSC installed, same as most car owners have someone install the radio. If they wanted to know about electronics, they'd do it themselves.

If they install the radio themselves, they do it same way most own car installers would do.

That has nothing to do with radio operations, and any course that included both I'd ignore.
 
Well pardon us inferior beings for being on the same planet!!
I may well have asked a SILLY question in your eyes, not
being a radio technician i was merely asking for advice
Solitaire answered the question,without belittling me.
If i ask Solitaire for further advice please refrain from
voicing your rather lofted opinions, i just read your
profile, says it all about you really, a total knowall
 
It isn't so much that the digital data travels further, it is the fact the receiver can pick it out of the noise (sensitivity).

The better the radio the better the sensitivity, and lower the noise floor. To get the noise down as low as possible requires more expensive components. Noise is just that, the hum on your HiFi is noise from the amplifier stages.

This is one of the reasons premium sets like Icom are more expensive than say Silva. Unfortunately, as Steve has requested on a mobo thread a while back, the magazines do not test the sets in lab conditions they just button press and give the cheapest set like Standard a big thumbs up, yet it could be as noisy as a ba$tard. Not a problem close range, but if you start sailing offshore with cheap and cheerful sets you will start to loose comms in the noise before a good radio.

If you think about the power of the incoming signal, it can measured in microwatts, the amount of amplification the radio requires to change that from a minute little power that hits your antenna to something you hear coming out of the speaker is massive respectfully. The biggest problem with radios, is that the noise present is also amplified along with your wanted signal. It can be the difference for example between a maplin 12p resistor and a high spec £3.00 jobbie that can make all the difference.

You pays your money etc.

hope that helps (hope I got it right too /forums/images/graemlins/wink.gif )
 
which is why I used the phrase 'carry further' rather than travel further.
I think Steve has lost sight of what the course is about, and is using his credentials to carry an arguement, rather than understand that many people really don't know how to use a DSC set.

Not everyone has his level of understanding, and to many, the sight of all those buttons and software is scary.


My mum tonight wanted me to order a new battery for her mobile phone. Just getting the information on what model it was took nearly 20 minutes, and I was being patient.
 
[ QUOTE ]
Procedures and how to use the equipment are excellent for keeping discipline within the band, and I'm a great beleiver in that, but they are only part of the knowledge required to be conversant with the system.
It's a bit like me saying to you, yeah we'll do the day skipper course but I dont want you to teach me anything about buoys and lights.



[/ QUOTE ]

/forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif In my wildest imagination I cannot see how you come to that conclusion!
 
[ QUOTE ]
None of this extremely simple stuff is particularly "geeky", and I could teach all of that in under two hours to anybody with average intelligence.
Steve.

[/ QUOTE ]

I think you're wrong. You are forgetting that you have a fundamental knowledge, you have knowledge of how electrickery travels down wires. You know what impedance actually means for example.

Go and explain to your mum in two hours, to a level so she could telephone me and explain with examples why impedance matching is so important, she should be able to tell me what a standing wave is and how it will affect the transmitted signal, why a short circuit measured on a multimeter is not a short circuit to RF.

It is not a question of intelligence, most people leave school with a basic understanding of DC series and parallel circuits. RF is a complex subject that although not impossibly difficult, requires and accumulation of many pre subjects in electronics to understand what is going on.

Plus, 96% of the class would fall asleep.

The information is out there for those who wish to learn more, but it certainly should not be lumped in with an operators licence. That would be like me needing to strip a car engine down to pass my driving test, even though I could /forums/images/graemlins/wink.gif
 
Ooh er..sorry..and I didnt mean to belittle you. My apologies.
There are a lot of questions asked on this forum about radio and a lot of these are basic questions which should be addressed within the RYA course.
I not even having a go a David.
The problem is with the RYA, and also that the perception of a RYA radio instructor is that they know everything about radio, so should be able to answer all manner of marine radio questions.
The reality is that these guys have no specialist knowledge over and above that required to teach the rather limited DSC radio course, or at least in my experience
they havent. Sure you'll find the odd few who may also be radio amateurs and have good knowledge, but the majority are the chaps who teach sailing courses.
As explained in a previous message there is a lot more to being conversant with a radio system than just knowing how to press the buttons and what to say, but that is not saying that as a user you have to know all the technical details.
Certainly you should know about installation issues...because the vast majority of leisure sailors fit their own equipment. I wonder how many of those even bother to borrow a SWR meter and check the antenna matching?
Surely you can see what I am saying here, that there is a lot more to it..not neccesarily very technical stuff, than just procedures.

I'm a nice guy really....honest...only a know it all about radio stuff....because that is my profession....and I generally only comment on stuff which is Marine Electronics and Nav (PC) systems related... nothing else, because I dont have sufficient knowledge to do so.
Please accept my apology.

Steve.
 
[ QUOTE ]
which is why I used the phrase 'carry further' rather than travel further.


[/ QUOTE ]

I'm sorry Brendan I was trying to explain what Steve was telling you in a more simple English way. If you knew the answer why did you ask the question. I was not trying to put one over you or be patronising, but Steve tends to write like a technical publication which is not a bad thing, but I often see people go for the ???? key on their keyboards.

I am sure like any specialist subject you could bamboozle with science, though I would never dare ask what your specialist subject is as we are not married.
 
your answer was about sensitivity and expense of receiver. Not about whether digital is better at long distance than analogue.

Digital does in theory have an advantage, tho I'm not completely convinced in reality it's as great as it's proponents state.
 
Because you are only giving part of the information.
It's about other things as well, knowing the limitations of the system for instance and how to maintain it adequately, knowing how to recognise if there's a problem.
So many things...procedures are just one small part.
I dont expect everyone to be an engineer, just that those who are self installing should have been given at least basic instruction on how to do so and the RYA is best placed to do this as part of decent radio course.
Or maybe the RYA should run an additional course over and above the procedure course for those that want it. At the moment the DSC course is all there is.
They run a deisel engine course so why not a further radio course??

It's odd really that any SOLAS commercial vessel has to have a certified radio system installed by a qualified person...and yet many many thousands of leisure sailors put to sea on a wing and a prayer with their radio systems.
Are our lives any less valuable than commercial mariners?


Anyway I can see I'm not going to win this one, so I will retire gracefully.

Steve.
 
I thought the radio officer had been removed and this was part of the reason DSC was introduced.

I could be wrong.
 
I really can't see where you are coming from on this issue. Most don't know vhf protocol, never mind DSC. To extend it to knowing installation and maintenance is simply silly.


Those that can install a DSC radio are probably not going to need instruction on which buttons to press if they need to use it.
 
The problem is Brendan that there is no theory which gives it advantage, certainly not on angle modulated systems, (Phase and Frequency Modulation).
On amplitude modulated derivatives like SSB if you shout louder into the mike you can get a higher output. The same is not true for F3E or G3E. The carrier amplitude of the signal always remains the same. It is the "deviation" which changes ie the frequency or phase shifts, so it can not have any bearing whatsoever on range persee.
You have to put in sufficient signal to open the squelch of the reciever and that is dependent on how many microvolts are being received at the antenna ie how great the electomagnetic field being recieved.
That is a function of the carrier power, nothing to do with whatever signal that carrier is being modulated with, whether digital, voice, Pulse Code Modulation or the bonzo dog do dah band playing the into and outro into your mike..it will always be the same.

Steve.
 
That's true, but correct me if I'm wrong, in that the equipment must be approved and installed by a qualified fitter and a certificate issued.
I dont think cunard are permitted to pop down to the local chandlery and have the chief stoker rig up a DSC on the bridge..but I may be wrong...

Steve.
 
That doesn't answer the question tho. Digital processing means that signals have error handling built in. So even if signal is not good enough for voice communications, it can still handle digital communications, thereby digital communications can be held over a greater distance than voice.

It's the error handling that makes a difference, in exactly the same way it does on computer networks?
 
Back to the question -

having done my original VHF abt 20 years ago and my DSC last year, was useful. Actually, the DSC Mayday bit could have been taught in abt half an hour. But did learn I can no longer call PAN PAN MEDICO when I break one of the crew.

The bits the instructor got a little confused on (but recovered well) were DSC urgency calls and Mayday relays.

And not everyone passes. One hugely thick sloaney girl was failing the course for the second time and still couldn't even grasp the use of the PTT button - some people should stick to mobile phones and chiswick tractors IMHO.
 
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